Rotational atherectomy device with fluid inflatable support elements and two torque transmitting coils

ABSTRACT

A rotational atherectomy device for removing a stenotic tissue from a vessel of a patient is disclosed. The device comprises a rotatable, flexible, hollow drive shaft having a fluid impermeable wall defining a fluid impermeable lumen of the drive shaft and, an abrasive element mounted to a distal end portion of the drive shaft proximal to and spaced away from a distal support element formed at a distal end of the drive shaft, the distal support element being inflatable by pressurized fluid which flows in an antegrade direction through said lumen of the drive shaft and is at least partially re-directed into the distal fluid inflatable support element.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. application Ser. No. 13/415,221 filed onMar. 8, 2012 by Dr. Leonid Shturman, which is a continuation of U.S.application Ser. No. 12/373,477 filed on Jan. 12, 2009 by Dr. LeonidShturman, which is a national phase application based onPCT/EP2007/056521 filed on Jun. 28, 2007, which claims priority to GBPatent Application No. 0613982.8 filed on Jul. 13, 2006, the contents ofthese prior applications being incorporated herein by reference.

BACKGROUND

1. Field

The present invention relates to a rotational atherectomy device forremoving or reducing stenotic lesions in blood vessels such as a humanartery by rotating an abrasive element within the vessel to partially orcompletely ablate the unwanted material.

2. Description of Related Art

Atherosclerosis, the clogging of arteries, is a leading cause ofcoronary heart disease. Blood flow through the peripheral arteries(e.g., carotid, femoral, renal etc.), is similarly affected by thedevelopment of atherosclerotic blockages. A conventional method ofremoving or reducing blockages in blood vessels is known as rotationalatherectomy. Such a method and a device for performing the method aredescribed in, for example, U.S. Pat. No. 4,990,134 to Auth. According toAuth, a long guidewire is advanced into the diseased blood vessel acrossthe stenotic lesion. A hollow drive shaft formed from a singe layer oftorque transmitting coiled wire(s) is the advanced over the guidewire.The distal end of the drive shaft terminates in a burr provided with anabrasive surface formed from diamond grit or diamond particles. The burris positioned against the occlusion and the drive shaft rotated atextremely high speeds (e.g., 20,000-160,000 rpm). As the burr rotates,the physician slowly advances it so that the abrasive surface of theburr scrapes against the occluding tissue and disintegrates it, reducingthe occlusion and improving the blood flow through the vessel.

It is also known from U.S. Pat. No. 6,132,444 to Shturman (the instantinventor) et al., to provide a drive shaft with an eccentric enlargeddiameter segment positioned proximally to and spaced away from thedistal end of the drive shaft. According to U.S. Pat. No. 6,132,444 toShturman, abrasive particles are located around a maximum diameter ofsaid eccentric enlarged diameter segment of the drive shaft therebyforming an eccentric abrasive element positioned proximally to andspaced away from the distal end of the drive shaft. According to U.S.Pat. No. 6,132,444 to Shturman, the drive shaft is formed from a singlelayer of torque transmitting coiled wire(s).

The prior art rotational atherectomy devices such as those referred toabove comprise an elongated drive shaft rotatable around a stationaryguidewire. A long proximal portion of the drive shaft is rotatablewithin an elongated stationary drive shaft sheath, said drive shaftsheath forming an annular lumen between the stationary sheath and therotatable drive shaft. A saline solution or special lubricating fluid ispumped into the annular lumen between the stationary sheath and therotatable drive shaft. A portion of said saline solution or speciallubricating fluid is able to pass between adjacent wire turns of thedrive shaft into a second annular lumen formed between the drive shaftand the guidewire thereby reducing friction between the drive shaft andthe guidewire. In all of the prior art rotational atherectomy devicesreferred to above the antegrade flowing saline solution or speciallubricating fluid enters the treated vessel from distal end of thestationary drive shaft sheath and thereby entrains and propels distallyin an antegrade direction along the treated vessel abraded particles(debris) removed by the abrasive element. The distal migration of theabraded particles (debris) in an antegrade direction and embolisation ofvery small diameter arteries or capillaries by said abraded particles isof major concern to physicians who practice in this field. Clearly, theexistence of particulate matter in the blood stream is undesirable andcan cause potentially life-threatening complications, especially if theparticles are over a certain size.

Although the potentially detrimental effect caused by the presence ofabraded particles in the blood vessels is reduced if they are very smallmicroparticles, it is much more preferable to remove from the treatedblood vessel any debris abraded or otherwise released from the stenoticlesion during treatment and thereby prevent migration of debris to otherlocations along the treated blood vessel.

A rotational atherectomy device, described in U.S. Pat. No. 5,681,336(to Clement et al.), has been proposed. This device attempts to preventmigration of abraded particles distally along the treated blood vesselby removing the ablated material from the blood vessel whilst the deviceis in use. The rotational atherectomy device known from U.S. Pat. No.5,681,336 (to Clement et al.) has a complicated construction and isdifficult to manufacture on a commercial scale.

A number of disadvantages associated with the known rotationalatherectomy devices have been addressed in WO 2006/126076 to Shturman(the instant inventor). All of the the embodiments described in WO2006/126076 comprise a rotatable fluid impermeable drive shaft and allowdelivery of pressurized fluid from a lumen of the rotatable fluidimpermeable drive shaft into the treated vessel distal to the abrasiveelement so that at least a portion of said fluid flows in a retrogradedirection along the treated vessel between the stenotic lesion and thevessel wall and entrains the abraded particles removed by the abrasiveelement. The retrograde flowing fluid and entrained abraded particlesare aspirated from the treated vessel and out of the patient's body.

All embodiments shown in WO 2006/126076 illustrate a torque transmittingelement of the fluid impermeable drive shaft being formed by a singlemultifilament metal torque transmitting coil which extends distallythrough and distal to the abrasive element. An atherectomy device havingthis design allows excellent transmission of torque to the abrasiveelement by the torque transmitting coil, but does not enable the deviceto have a sufficiently small transverse cross-sectional dimension tocross very tight stenotic lesions.

SUMMARY

The present invention seeks to provide a rotational atherectomy devicewith transverse cross-sectional dimensions sufficiently small to crossvery tight stenotic lesions.

According to the present invention, there is provided a rotationalatherectomy device for removing a stenotic tissue from a vessel of apatient, the device comprising a rotatable, flexible, hollow drive shafthaving a fluid impermeable wall defining a fluid impermeable lumen ofthe drive shaft and, an abrasive element mounted to a distal end portionof the drive shaft proximal to and spaced away from a distal supportelement formed at a distal end of the drive shaft, the distal supportelement being inflatable by pressurized fluid which flows in anantegrade direction through said lumen of the drive shaft and is atleast partially re-directed into the distal fluid inflatable supportelement, wherein the distal fluid inflatable support element has anouter wall comprising an outflow opening located such that said outflowopening faces an inner surface of a treated vessel during rotation ofthe drive shaft so that a flow of fluid through said outflow openingforms a layer of fluid between the outer wall of the rotating fluidinflated distal support element and a wall of the treated vessel to forma fluid bearing between the outer wall of the rotating fluid inflateddistal support element and the wall of the treated vessel, the driveshaft being comprised of at least one fluid impermeable membrane and atleast two torque transmitting coils, one of said coils extendingdistally beyond the distal end of the other coil and conveying torque tothe abrasive element mounted to the drive shaft distal to and spacedaway from a portion of the drive shaft formed from the fluid impermeablemembrane and said torque transmitting coils.

In a preferred embodiment, the outer wall of the distal fluid inflatablesupport element has a plurality of outflow openings located such that atleast one of said outflow openings, during rotation of the drive shaft,faces an inner surface of a treated vessel so that fluid flowing throughthe outflow openings forms a layer of fluid between the outer wall ofthe rotating fluid inflated distal support element and a wall of thetreated vessel to form a fluid bearing between the outer wall of therotating fluid inflated distal support element and the wall of thetreated vessel.

In one embodiment of the invention, the abrasive element has a slot andis mounted to the drive shaft such that said slot extends in alongitudinal direction and is attached to the drive shaft by a flexiblestrap which extends through said slot and is connected to the driveshaft distal and proximal to the abrasive element.

In another embodiment, the abrasive element has a slot and is mounted tothe drive shaft by a flexible strap which extends through said slot andis wrapped circumferentially around the drive shaft. Preferably, theabrasive element has a slot and is mounted to the drive shaft by aflexible strap which extends through said slot and is wrappedcircumferentially around the drive shaft distal to and spaced away fromthe distal end of the torque transmitting coil.

The flexible strap may have leading and trailing edge portions relativeto the direction of rotation of the drive shaft, wherein the trailingedge portion of the flexible strap at least partially overlaps theleading edge portion when wrapped around the drive shaft. The leadingand trailing edge portions of the flexible strap can be bonded to eachother in their overlapping region.

In one embodiment, the abrasive element has a leading edge and atrailing edge relative to the direction of rotation of the drive shaft,the leading edge of the abrasive element being thinner than the trailingedge so that, during rotation of the drive shaft, an abrasive surface ofthe abrasive element engages and abrades stenotic tissue only by athicker portion of the abrasive element, said thicker portion of theabrasive element being spaced away from the leading edge of the abrasiveelement.

In another embodiment, the abrasive element has a rotationally leadingedge and a rotationally trailing edge relative to the direction ofrotation of the drive shaft, the rotationally leading edge of theabrasive element being thinner than the trailing edge so that the degreeof engagement of the abrasive element with the stenotic tissue graduallyincreases during a revolution of the drive shaft. The abrasive elementmay extend around less than a half of the circumference of the driveshaft. Alternatively, the abrasive element extends around less than athird of a circumference of the drive shaft or, it may extend around theentire circumference of the drive shaft.

In one embodiment, the fluid impermeable drive shaft has a longitudinalaxis and the distal fluid inflatable support element has a centre ofmass offset from the longitudinal axis of the drive shaft when thedistal inflatable support element is fluid inflated. Preferably, theouter wall of the distal fluid inflatable support element defines afluid inflatable space that extends only partially around acircumference of the drive shaft so that, when the distal inflatablesupport element is fluid inflated, its centre of mass is offset from alongitudinal axis of the drive shaft in one direction, the distal fluidinflated support element acting, during rotation of the drive shaft, asa counterweight to the abrasive element which has its centre of massoffset from the longitudinal axis of the drive shaft in the oppositedirection.

In one preferred embodiment, the fluid impermeable drive shaft isprovided with a proximal fluid inflatable support element locatedproximal to and spaced away from the abrasive element, the proximalfluid inflatable support element having an outer wall. The proximalfluid inflatable support element may comprise an inner wall having aninflow aperture therein so that a portion of fluid flowing in anantegrade direction through the drive shaft is re-directed through theinflow aperture into the inflatable support element to inflate saidproximal fluid inflatable support element.

In one embodiment, the proximal fluid inflatable support element has acentre of mass offset from the longitudinal axis of the drive shaft whenthe proximal inflatable support element is fluid inflated.

In one preferred embodiment, the outer wall of the proximal fluidinflatable support element comprises an outflow opening located suchthat said outflow opening faces an inner surface of a treated vesselduring rotation of the drive shaft so that a flow of fluid through saidoutflow opening forms a layer of fluid between the outer wall of therotating fluid inflated proximal support element and a wall of thetreated vessel to form a fluid bearing between the outer wall of therotating fluid inflated proximal support element and the wall of thetreated vessel.

The outer wall of the proximal fluid inflatable support elementpreferably has a plurality of outflow openings located such that atleast one of said outflow openings, during rotation of the drive shaft,faces an inner surface of a treated vessel so that fluid flowing throughthe outflow openings forms a layer of fluid between the outer wall ofthe rotating fluid inflated proximal support element and a wall of thetreated vessel to form a fluid bearing between the outer wall of therotating fluid inflated proximal support element and the wall of thetreated vessel.

The outer wall of the proximal fluid inflatable support elementpreferably defines a fluid inflatable space that extends only partiallyaround a circumference of the drive shaft so that, when the proximalinflatable support element is fluid inflated, its centre of mass isoffset from a longitudinal axis of the drive shaft in one direction, theproximal fluid inflated support element acting, during rotation of thedrive shaft, as a counterweight to the abrasive element which has itscentre of mass offset from the longitudinal axis of the drive shaft inthe opposite direction.

Preferably, in the first embodiment, the fluid inflatable space withinboth the distal and proximal fluid inflatable support elements extendscircumferentially only partially around circumferential segments of thedrive shaft which are spaced away in one direction with respect to thelongitudinal axis of the drive shaft so that, when both the distal andproximal fluid inflatable support elements are inflated by fluid, theircenters of mass become offset from a longitudinal axis of the driveshaft in said one direction and the distal and proximal fluid inflatablesupport elements act as counterweights to the abrasive element which islocated on the drive shaft between the support elements and has itscentre of mass offset from the longitudinal axis of the drive shaft inthe opposite direction.

Conveniently, a fluid inflatable space within the distal fluidinflatable support element extends uniformly around an entirecircumference of the drive shaft to provide the distal support elementwith a centre of mass which is coaxial with a longitudinal axis of thedrive shaft when said distal support element is fluid inflated.

In one embodiment, there is a plurality of openings in the outer wall ofthe fluid inflatable distal support element, said openings being locatedaround the circumference of the outer wall of the fluid inflatabledistal support element such that, during rotation of the drive shaft,flows of fluid through the openings form a layer of fluid between theouter wall of the fluid inflated distal support element and a wall ofthe treated vessel, said layer of fluid forming a fluid bearing betweenthe outer wall of the rotating fluid inflated distal support element andthe wall of the treated vessel.

There may be a plurality of openings in the outer wall of the fluidinflatable distal support element, said openings being located aroundthe circumference of the outer wall of the fluid inflatable distalsupport element such that, during rotation of the drive shaft, at leastone of said openings faces an inner surface of a treated vessel, so thatflows of fluid through the openings form a layer of fluid between theouter wall of the fluid inflated distal support element and a wall ofthe treated vessel, said layer of fluid forming a fluid bearing betweenthe outer wall of the rotating fluid inflated distal support element andthe wall of the treated vessel.

In one embodiment, a fluid inflatable space within the proximal fluidinflatable support element extends uniformly around an entirecircumference of the drive shaft to provide a fluid inflated proximalsupport element with a centre of mass which is coaxial with alongitudinal axis of the drive shaft.

In one embodiment there is a plurality of openings in the outer wall ofthe fluid inflatable proximal support element, said openings beinglocated around the circumference of the outer wall of the fluidinflatable proximal support element such that, during rotation of thedrive shaft, flows of fluid through the openings form a layer of fluidbetween the outer wall of the fluid inflated proximal support elementand a wall of the treated vessel, said layer of fluid forming a fluidbearing between the outer wall of the rotating fluid inflated proximalsupport element and the wall of the treated vessel. Preferably, there isa plurality of openings in the outer wall of the fluid inflatableproximal support element, said openings being located around thecircumference of the outer wall of the fluid inflatable proximal supportelement such that, during rotation of the drive shaft, at least one ofsaid openings is facing an inner surface of a treated vessel so thatflows of fluid through the openings form a layer of fluid between theouter wall of the fluid inflated proximal support element and a wall ofthe treated vessel, said layer of fluid forming a fluid bearing betweenthe outer wall of the rotating fluid inflated proximal support elementand the wall of the treated vessel.

In one embodiment, the fluid impermeable membrane extends distally underand beyond the abrasive element and is folded on itself at a distal endof the drive shaft to form the distal fluid inflatable support elementbetween an inner and outer layers of said folded membrane, the outerlayer of the membrane forming an outer wall of the distal fluidinflatable support element and the inner layer of the membrane formingan inner wall of the distal fluid inflatable support element, the innerwall of the inflatable support element having an aperture therein sothat a portion of fluid flowing in an antegrade direction through thedrive shaft is re-directed through the aperture into the distal fluidinflatable support element to inflate said distal support element.

The inner and outer layers of the folded fluid impermeable membrane maybe connected or bonded to each other at least just proximal to thedistal fluid inflatable support element. Preferably, the inner and outerlayers of the folded fluid impermeable membrane should be connected orbonded to each other around an entire circumference of the drive shaft.

In one embodiment, the outer layer of the folded fluid impermeablemembrane, after forming the outer wall of the distal fluid inflatablesupport element, extends further proximally to form an outer wall of theproximal fluid inflatable support element. The inner and outer layers ofthe folded fluid impermeable membrane may be connected or bonded to eachother at least just distal and proximal to the proximal fluid inflatablesupport element. Preferably, the inner and outer layers of the foldedfluid impermeable membrane should be connected or bonded to each otheraround an entire circumference of the drive shaft.

The distal fluid inflatable support element preferably has an inner walldefined by the inner layer of the fluid impermeable membrane, the innerwall having an inflow aperture therein so that a portion of the fluidflowing in an antegrade direction through the drive shaft is redirectedthrough the inflow aperture into the proximal fluid inflatable supportelement to inflate said proximal support element. Preferably, theaperture through which fluid enters the distal inflatable supportelement and the opening(s) in the outer wall of the inflated distalinflatable support element through which fluid exits the distalinflatable support element are configured so that the distal inflatablesupport element is kept inflated by the pressure of the fluid flowingthrough the inflatable support element.

The aperture through which fluid enters the distal inflatable supportelement may be larger than the opening(s) in the outer wall of theinflated distal inflatable support element through which fluid exits thedistal inflatable support element so that the distal inflatable supportelement is kept inflated by the pressure of the fluid flowing throughthe inflatable support element.

In one embodiment, the abrasive element has a slot and is mounted to thedrive shaft by a flexible strap which extends through said slot and iswrapped around the membrane proximal to and spaced away from the distalfluid inflatable support element. The flexible strap is preferablywrapped around the membrane distal to and spaced away from that portionof the drive shaft which is formed from the fluid impermeable membraneand the torque transmitting coils. Preferably, the flexible strap iswrapped around the outer layer of the folded fluid impermeable membrane.

In another embodiment, the abrasive element has a slot and is mounted tothe drive shaft such that said slot extends in a longitudinal directionand is attached to the fluid impermeable membrane by a flexible strapwhich extends through said slot and is connected to the drive shaftdistal and proximal to the abrasive element. The outer layer of thefolded fluid impermeable membrane, after forming the outer wall of thedistal fluid inflatable support element, may extend further proximallyto form an outer wall of the proximal fluid inflatable support elementand the flexible strap, which mounts the abrasive element to the driveshaft, extends between the inner and outer layers of the folded fluidimpermeable membrane both distal and proximal to the abrasive element.

The outer layer of the folded fluid impermeable membrane convenientlyhas an opening through which an abrasive surface of the abrasive elementat least partially protrudes above a surface of the outer layer of thefolded fluid impermeable membrane.

In one embodiment of the invention, the torque transmitting coils aredisposed coaxially with respect to each other, one of two coils being aninner torque transmitting coil and the other torque transmitting coilbeing an outer torque transmitting coil, the inner and the outer torquetransmitting coils being wound in opposite directions so that, when thedrive shaft is rotated, the outer torque transmitting coil preventsunwinding of the inner torque transmitting coil.

The fluid impermeable membrane may line the inner torque transmittingcoil. Alternatively, the fluid impermeable membrane is disposed aroundthe torque transmitting coils. Preferably, the fluid impermeablemembrane is sandwiched between the torque transmitting coils.

In one embodiment, the abrasive element extends around the entirecircumference of the drive shaft.

In one embodiment, a valve is formed at the distal end of the driveshaft. Preferably, the drive shaft may comprise a radially inwardlyextending shoulder located at or just proximal to the distal end of thedrive shaft. In this embodiment, the device may also comprise a roundedelement configured to be advanced to a distal end of the drive shaftwhere it is prevented from exiting the drive shaft by the radiallyinwardly extending shoulder, thereby occluding the distal end of thedrive shaft and thereby at least partially preventing flow of fluidthrough the very distal end of the drive shaft and assisting in theredirection of the flow of fluid into the fluid inflatable supportelements. The radially inwardly extending shoulder can be formedintegrally with a distal end of the inner torque transmitting coil.

According to yet another embodiment of the invention, there is provideda rotational atherectomy device for removing a stenotic tissue from avessel of a patient, the device comprising an abrasive element mountedto a rotatable, flexible, hollow, drive shaft, the drive shaft comprisedby a fluid impermeable membrane and two coaxially disposed torquetransmitting coils, the membrane and one of two coils extending distallybeyond the abrasive element which is attached to the membrane distal toa distal end of the other torque transmitting coil and proximal to andspaced away from a distal fluid inflatable support element formed bysaid fluid impermeable membrane at a distal end of the drive shaft, thedistal fluid inflatable support element including at least two openings,an inflow opening communicating a fluid impermeable lumen of the driveshaft with an inflatable space of the distal fluid inflatable supportelement and an outflow opening located in an outer wall of the distalfluid inflatable support element and communicating the interior space ofthe distal fluid inflatable support element with a vascular space withinthe vessel of the patient, said outflow opening having an axis whichforms an angle of about ninety (90) degrees with a longitudinal axis ofthe drive shaft when the distal fluid inflatable support element isinflated.

According to yet another embodiment of the invention, there is provideda rotational atherectomy device for removing a stenotic tissue from avessel of a patient, the device comprising an abrasive element mountedto a rotatable, flexible, hollow drive shaft, the drive shaft comprisedby a fluid impermeable membrane sandwiched between inner and outertorque transmitting coils, the inner torque transmitting coils and themembrane extending distally beyond the abrasive element which isattached to the membrane distal to a distal end of the outer torquetransmitting coil and proximal to and spaced away from a distal fluidinflatable support element formed by said fluid impermeable membrane ata distal end of the drive shaft, the distal fluid inflatable supportelement including at least two openings, an inflow opening communicatinga fluid impermeable lumen of the drive shaft with an inflatable space ofthe distal fluid inflatable support element and an outflow openinglocated in an outer wall of the distal fluid inflatable support elementand communicating the interior space of the distal fluid inflatablesupport element with a vascular space within the vessel of a patient,said outflow opening having an axis which forms an angle of about ninety(90) degrees with a longitudinal axis of the drive shaft when the distalfluid inflatable support element is inflated, so that in a rotatingfluid inflated distal support element a flow of fluid through theoutflow opening forms a thin layer of fluid between the outer wall ofthe fluid inflated distal support element and an inner surface of a wallof the vessel which is being treated.

In one embodiment, the drive shaft is provided with a solid proximalsupport element located proximal to and spaced away from the abrasiveelement, the membrane that forms a fluid impermeable lumen for theantegrade flow of fluid through the drive shaft into the distal fluidinflatable support element also forming a lumen for the antegrade flowof fluid through the drive shaft into an outflow channel extendingthrough said solid proximal support element, the solid proximal supportelement having a rounded outer surface, said outflow channel having anoutflow opening in the rounded outer surface of the solid proximalsupport element such that, during rotation of the drive shaft, saidoutflow opening on the outer surface of the solid proximal supportelement is facing an inner surface of a treated vessel so that a flow offluid out of said outflow opening forms a layer of fluid between thesolid proximal support element and a wall of the treated vessel duringrotation of the drive shaft, said layer of fluid forming a fluid bearingbetween the rotating solid proximal support element and the wall of thetreated vessel.

It should be appreciated that the present invention covers two mostpreferred embodiments namely, a first most preferred embodiment in whichthe fluid inflatable support elements are asymmetrical with respect tothe longitudinal axis of the drive shaft and, a second most preferredembodiment in which the fluid inflatable support elements are symmetricwith respect to the longitudinal axis of the drive shaft. However, itwill be appreciated that, in all the embodiments, the asymmetric andsymmetric fluid inflatable elements comprise outflow openings locatedsuch that, in the rotating drive shaft, fluid flowing through saidopenings forms fluid bearings between outer walls of said inflatableelements and the wall of the treated vessel.

It should be noted that throughout this specification, reference is madeto “distal” and “proximal” ends and to flow of fluid in an “antegrade”and “retrograde” direction. For the avoidance of doubt, the distal endis considered to refer to the end of the device which is inserted intothe vessel in the body of the patient and the proximal end is the end ofthe device which remains outside the body of the patient and which canbe connected to a handle assembly for both rotating and longitudinallymoving the drive shaft within the treated vessel. “Antegrade” flowrefers to a direction of flow from the proximal towards the distal endof the device. Similarly, “retrograde” flow refers to a direction offlow in the opposite direction, i.e. from the distal towards theproximal end of the device.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of exampleonly, in conjunction with the following drawings, in which:

FIG. 1 is a side sectional view of the distal end portion of therotational atherectomy device illustrating attachment of an abrasiveelement to a fluid impermeable drive shaft by a longitudinally extendingstrap and showing fluid inflatable support elements of the drive shaftin their deflated state;

FIG. 2 is similar to FIG. 1, except it illustrates flow of fluid intoand out of the inflated support elements, the fluid inflated supportelements having their centers of mass spaced radially away from thelongitudinal axis of the drive shaft;

FIG. 3 shows an enlarged cross-sectional view of the distal fluidinflatable support element taken along a line A-A in FIG. 1;

FIG. 4 is an enlarged cross-sectional view taken along a line B-B inFIG. 1 and illustrates attachment of the abrasive element to the driveshaft;

FIG. 5 shows an enlarged cross-sectional view of the proximal inflatablesupport element taken along a line C-C in FIG. 1;

FIG. 6 shows an enlarged cross-sectional view taken along a line D-D inFIG. 2 and illustrating flow of fluid into and out of the distal fluidinflated support element;

FIG. 7 is similar to FIG. 4 except that it is taken along a line E-E inFIG. 2;

FIG. 8 shows an enlarged cross-sectional view taken along a line F-F inFIG. 2 and illustrating flow of fluid into and out of the proximal fluidinflated support element;

FIG. 9 is a sectional side elevation of a portion of a blood vesselcontaining a stenotic lesion and shows a guidewire which has beenalready advanced across the stenotic lesion to be treated;

FIG. 10 is a side sectional view of the portion of the blood vesselshown in FIG. 9 and illustrates advancement of the fluid impermeabledrive shaft over the guidewire;

FIG. 11 is similar to FIG. 10, but illustrates that the drive shaft hasbeen advanced across the stenotic lesion to a position in which thedistal fluid inflatable support element is located distal to thestenotic lesion and the proximal fluid inflatable support element isstill proximal to the stenotic lesion to be treated;

FIG. 12 is a side sectional view illustrating withdrawal of theguidewire from the drive shaft;

FIG. 13 is a side sectional view illustrating that the guidewire hasbeen completely withdrawn from the drive shaft;

FIG. 14 is a side sectional view illustrating antegrade flow of fluidalong the fluid impermeable drive shaft, inflation of the fluidinflatable support elements and retrograde flow of fluid around thedrive shaft;

FIGS. 15 through 26 illustrate abrading of the stenotic lesion by therotating abrasive element and formation of fluid bearings between theinner surface of the vessel and the outer walls of the rotating fluidinflated support elements, said fluid bearings being formed by flow offluid through the openings in the outer walls of the fluid inflatedsupport elements;

FIG. 27 illustrates that antegrade flow of fluid through the drive shaftand retrograde flow of fluid across the treated stenotic lesion iscontinued for at least a short period of time after rotation of thedrive shaft has been stopped;

FIG. 28 illustrates that the fluid inflatable support elements have beendeflated and the drive shaft is ready to be removed from the treatedvessel;

FIGS. 29 and 30 illustrate the removal of the drive shaft from thetreated vessel and appearance of the treated vessel after removal of thedrive shaft;

FIGS. 31 through 34 are similar to FIGS. 15 through 26 except that theyillustrate abrading of a very tight stenotic lesion from a largediameter vessel by the rotational atherectomy device with a smalldiameter drive shaft;

FIGS. 35 through 39 show enlarged views of the abrasive element and thefluid inflatable support elements to illustrate best how the flows offluid out of the rotating fluid inflated support elements form fluidbearings between the outer walls of the rotating fluid inflated supportelements and the wall of the treated vessel;

FIG. 40 is similar to FIG. 1 except that it illustrates the abrasiveelement being attached to the drive shaft by the longitudinallyextending strap which is made integrally with the fluid impermeablemembrane of the drive shaft;

FIG. 41 is similar to FIG. 1 except that it illustrates the abrasiveelement being made integrally with the longitudinally extending strapwhich attaches the abrasive element to the drive shaft;

FIGS. 42 through 49 are similar to FIGS. 1 through 8 except that theyillustrate that the abrasive element is attached to the drive shaft by aflexible strap which extends around the drive shaft;

FIG. 50 is similar to FIG. 42 except that it illustrates fluidinflatable support elements which extend around the entire circumferenceof the drive shaft;

FIG. 51 is similar to FIG. 43 except that it illustrates flow of fluidinto and out of the fluid inflated support elements which extend aroundthe entire circumference of the drive;

FIGS. 52 through 55 illustrate the formation of fluid bearings betweenthe inner surface of the treated vessel and the outer walls of therotating fluid inflated support elements, each of the support elementshaving a fluid inflatable space which extends circumferentially aroundthe entire circumference of the drive shaft so that, in a curved vesselsaid support elements bias the abrasive element towards the innercurvature of the curved vessel and allow preferential removal ofstenotic tissue from the inner curvature of the treated curved vessel;

FIG. 56 illustrates in a transverse cross-section an abrasive elementwhich has its rotationally trailing edge made thicker than itsrotationally leading edge;

FIG. 57 illustrates the drive shaft which has the outer wall of itsproximal fluid inflatable support element formed by a membrane which isnot continuous with the membrane which forms the outer wall of thedistal fluid inflatable support element;

FIG. 58 illustrates that the fluid impermeable drive shaft has aradially inward extending shoulder located at or just proximal to thedistal end of the drive shaft;

FIGS. 59 and 60 show a rounded element being advanced to a distal end ofthe drive shaft and stopped from exiting from the drive shaft by theradially inward extending shoulder, thereby preventing flow of fluidthrough an opening at the distal end of the drive shaft and assisting inthe redirecting flow of fluid into the fluid inflatable supportelements;

FIG. 61 illustrates that the radially inward extending shoulder at thedistal end of the drive shaft has been formed integrally with the distalend of the inner torque transmitting coil;

FIG. 62 illustrates that a rounded element has been advanced to a distalend of the drive shaft and stopped from exiting from the drive shaft bythe radially inward extending shoulder, thereby preventing flow of fluidthrough an opening at the distal end of the drive shaft and assisting inthe redirecting flow of fluid into the fluid inflatable supportelements, the radially inward extending shoulder being formed integrallywith the inner torque transmitting coil;

FIG. 63 illustrates the distal end portion of the drive shaft with anasymmetric fluid inflatable distal support element and a solidasymmetric proximal support element, the fluid inflatable element shownin its deflated state, and;

FIG. 64 illustrates the distal end portion of the drive shaft with anasymmetric fluid inflatable distal support element and a solidasymmetric proximal support element, the fluid inflatable element shownin its inflated state.

DETAILED DESCRIPTION

In FIGS. 1 to 64, the atherectomy device is advanced across the stenoticlesion 330 over the guidewire 301. The direction of movement of thedevice is indicated by arrow marked “DM”, the antegrade flow of fluidbeing indicated by arrows “FF” and the flow of fluid in a retrogradedirection is indicated by arrows marked “R”. Arrows marked “FP”designate pressure of fluid which distends the support elements. Abradedparticles AP abraded from the stenotic lesion 330 are aspirated into alumen of a drive shaft sheath 5000 so that the retrograde flowing fluidand the abraded particles entrained in said fluid can be removed fromthe treated vessel and out of the patient's body.

FIGS. 1 through 8 illustrate in longitudinal and transversecross-sections a distal portion of the first most preferred embodimentof the rotational atherectomy device of the invention. The rotationalatherectomy device is comprised of an abrasive element 1 which ismounted to a rotatable, flexible, hollow, drive shaft 2 proximal to andspaced away from a distal end 6 of the drive shaft. The drive shaft 2comprises a fluid impermeable membrane 3 and a pair of coaxiallydisposed torque transmitting coils comprising an inner torquetransmitting coil 44 and, an outer torque transmitting coil 4. Both theinner torque transmitting coil 44 and the fluid impermeable membrane 3extend distally beyond the abrasive element 1 which is attached to themembrane 3 distal to and spaced away from a distal end 5 of the outertorque transmitting coil 4 and proximal to and spaced away from a distalfluid inflatable support element 10 formed by the fluid impermeablemembrane 3 at the distal end 6 of the drive shaft 2. The inner torquetransmitting coil 44 has its distal end 55 located at or just proximalto the distal end 6 of the drive shaft 2, thereby substantially aloneconveying torque to the abrasive element 1 and to the distal fluidinflatable support element 10 which are located distally and spaced awayfrom the distal end 5 of the outer torque transmitting coil 4. The fluidimpermeable membrane 3 is folded on itself at the distal end 6 of thedrive shaft 2 and forms the distal fluid inflatable support element 10between an inner 11 and outer 22 layers of the folded membrane 3. Theouter layer 22 of the membrane 3 forms an outer wall 222 of the distalfluid inflatable support element 10 and the inner layer 11 of themembrane 3 forms an inner wall 111 of the distal fluid inflatablesupport element 10. The inner wall 111 of the distal fluid inflatablesupport element 10 has an inflow aperture 15 therein. The inflowaperture 15 of the distal fluid inflatable support element 10communicates a lumen of the fluid impermeable drive shaft 2 with a fluidinflatable space 3000 of the distal fluid inflatable support element 10.FIG. 2 illustrates that a portion of flushing fluid FF flowing in anantegrade direction through the drive shaft 2 is redirected through theinflow aperture 15 into the distal fluid inflatable support element 10to inflate said distal inflatable support element.

It should be noted that the inner 11 and the outer 22 layers of thefolded membrane may be formed by either folding the membrane 3 back ontoitself or by inverting it.

FIG. 2 illustrates best that in order to form the distal fluidinflatable support element 10, the inner 11 and outer 22 layers of thefolded fluid impermeable membrane 3 are connected or bonded to eachother at least just proximal to the distal fluid inflatable supportelement 10. In this location, just proximal to the distal fluidinflatable support element 10, the inner 11 and the outer 22 layers ofthe membrane 3 are preferably connected or bonded to each other aroundthe entire circumference of the drive shaft 2.

In the most preferred embodiment of the invention the outer wall 222 ofthe distal fluid inflatable support element 10 has at least one outflowopening 20 which enables flow of fluid out of the distended fluidinflatable distal support element 10. The distal fluid inflatablesupport element 10 becomes distended by flow of fluid through an inflowaperture 15 in its inner wall 111. The inflow aperture 15 communicates alumen of the fluid impermeable drive shaft 2 with an inflatable space3000 within the distal fluid inflatable support element 10, saidinflatable space 3000 being at least partially defined by a fluidimpermeable membrane which forms the outer wall 222 of the distal fluidinflatable support element 10.

An area of the inflow aperture 15 through which fluid enters the distalinflatable support element 10 is larger than the area of the outflowopening(s) 20 through which fluid exits the distal inflatable supportelement 10 so that the distal fluid inflatable support element 10 iskept inflated by the pressure of the fluid flowing through the distalinflatable support element 10.

FIGS. 1, 2, 3 and 6 show the distal fluid inflatable support element 10which is asymmetric with respect to a longitudinal axis of the driveshaft. After being inflated by fluid, such asymmetric distal supportelement has its centre of mass CM spaced away from the longitudinal axisW-W of the drive shaft 2. FIGS. 1, 2 and 4 show an abrasive element 1which is mounted to the drive shaft 2 proximal to and spaced away fromthe asymmetric distal fluid inflatable support element 10. The abrasiveelement 1 extends only around a portion of the circumference of thedrive shaft 2 and has its centre of mass spaced radially away from thelongitudinal axis of the drive shaft. Preferably, the centre of mass CMof the asymmetric fluid inflated distal support element 10 is spacedradially away from the longitudinal axis W-W of the drive shaft in onedirection and the centre of mass of the abrasive element 1 is spacedradially away from the longitudinal axis W-W of the drive shaft inanother diametrically opposite direction, so that in a rotating driveshaft such asymmetric fluid inflated distal support element 10 acts as adistal fluid inflatable counterweight with respect to the abrasiveelement 1.

FIG. 2 illustrates that the outer wall 222 of the fluid inflated distalsupport element 10 is rounded and is bowing radially outwards at leastalong its longitudinally middle section which extends in a longitudinalcross-section between an outflow opening 20 which is locatedlongitudinally most distally within the outer wall 222 and anotheroutflow opening 20 which is located longitudinally most proximallywithin the outer wall 222.

Each outflow opening 20 in the outer wall 222 of the distal fluidinflatable support element has its own axis K-K. FIG. 2 illustrates thatthe asymmetric distal fluid inflatable support element 10 when inflatedhas at least one outflow opening 20 in its rounded outer wall 222located such that the axis K-K of the outflow opening 20 forms an acuteangle a of at least sixty (60) degrees with respect to the longitudinalaxis of the drive shaft. In the most preferred embodiment of theinvention, the asymmetric distal fluid inflatable support element 10when inflated has at least one outflow opening 20 in its outer wall 222located such that the axis K-K of the outflow opening 20 forms an angleβ of about ninety (90) degrees with respect to the longitudinal axis ofthe drive shaft. FIGS. 15 through 26 illustrate that in the rotatingasymmetric fluid inflated distal support element 10 at least one of theabove described outflow openings 20 is located such that its axis K-Kforms about a ninety (90) degrees angle with respect to the innersurface of the wall 300 of the treated vessel. Centrifugal forceattempts to press a rotating asymmetric fluid inflated distal supportelement 10 against the wall 300 of the treated vessel, but fluid exitingfrom the outflow opening 20 along its axis K-K at an angle of aboutninety (90) degrees with respect to the wall 300 of the vessel forms athin layer of fluid between the outer wall 222 of the fluid inflateddistal support element 10 and an inner surface of the wall 300 of thevessel. The formation of a thin layer of fluid between the outer wall222 of the rotating fluid inflated distal support element 10 and aninner surface of the wall 300 of the vessel is best illustrated in FIG.38. FIG. 38 shows a portion of the vascular wall 300 and a magnifiedview of the rotating fluid inflated distal support element 10 which hasits outer wall 222 separated from the inner surface of the wall 300 by athin layer of fluid exiting from the rotating extended distal supportelement 10 through outflow opening(s) 20 in its outer wall 222.Preferably, the fluid inflated distal support element 10 with the centreof mass radially spaced away from the longitudinal (rotational) axis ofthe drive shaft should have at least one outflow opening 20 in the outerwall 222 of the distal inflatable support element 10 located such thatat any time during rotation of the drive shaft 2 said outflow opening 20is facing an inner surface of the treated vessel so that a flow of fluidthrough the opening 20 forms a layer of fluid between the outer wall 222of the rotating fluid inflated distal support element 10 and the wall300 of a treated vessel. Said layer of fluid forms a fluid bearingbetween the outer wall 222 of the rotating fluid inflated distal supportelement 10 and the wall 300 of the treated vessel.

FIGS. 1 and 4 show one embodiment of the invention in which the abrasiveelement 1 has a longitudinally extending slot 40. The abrasive element 1is mounted to the drive shaft 2 by a flexible strap 41 which extendsthrough said slot 40 and is bonded to the fluid impermeable membraneboth distal and proximal to the abrasive element 1. Preferably, theouter layer 22 of the folded fluid impermeable membrane 3 extendsproximally beyond the abrasive element 1 and the flexible strap 41 whichmounts the abrasive element 1 to the drive shaft 2 extends between theinner 11 and outer 22 layers of the folded fluid impermeable membrane 3both distal and proximal to the abrasive element 1. The outer layer 22of the folded fluid impermeable membrane 3 has an opening through whichan abrasive surface of the abrasive element 1 protrudes above a surfaceof the outer layer 22 of the folded fluid impermeable membrane. FIG. 40shows one variation of the invention in which longitudinally extendingstrap 41′ is formed integrally with the outer layer 22 of the foldedfluid impermeable membrane 3. FIG. 40 illustrates that in suchembodiment the longitudinally extending strap 41′ is continuous with theouter layer 22 of the folded fluid impermeable membrane 3 distally tothe abrasive element 1 and is bonded to the fluid impermeable membrane 3proximally to the abrasive element 1.

FIG. 41 shows another variation of the invention in which the abrasiveelement 1′ is formed integrally with the longitudinally extending strap41″. Both the body of the abrasive element and the longitudinallyextending strap in such embodiment may be made from sufficientlyflexible material such as gold, the longitudinally extending strap beingmade substantially thinner than the body of the abrasive element inorder to make the strap sufficiently flexible. It should be noted thatthe rotational atherectomy devices with abrasive elements which do notextend around the entire circumference of the drive shaft may haveadvantages for crossing and abrading tight stenotic lesions. Therefore,any abrasive element which is attached to the drive shaft by alongitudinally extending strap should extend around less than a half ofthe circumference of the drive shaft and preferably even around lessthan a third of the circumference of the drive shaft.

In yet another variation of the first most preferred embodiment of theinvention shown in FIGS. 42 through 49 the abrasive element 101 has atransverse extending slot 140 and is mounted to the drive shaft 2 by aflexible strap 141 which extends through said slot and is wrapped aroundthe drive shaft 2. Preferably, in this embodiment the flexible strap 141is wrapped around the fluid impermeable membrane 3 distal to the distalend 5 of the outer torque transmitting coil 4. In the most preferredembodiment the flexible strap 141 is wrapped around the outer layer 22of the folded fluid impermeable membrane. FIG. 45 illustrates that theflexible strap 141 has leading and trailing edge portions relative tothe direction (arrow V) of rotation of the drive shaft 2, the trailingedge portion 142 of the flexible strap 141 extends around the driveshaft and at least partially overlaps the leading edge portion 143 ofsaid strap 141. The overlapping trailing 142 and leading 143 edgeportions of the flexible strap 141 are preferably bonded to each other.The abrasive element 101 also has a rotationally leading edge 801 and arotationally trailing edge 802 relative to the direction of rotation ofthe drive shaft 2.

FIG. 56 shows that the rotationally leading edge 801 of the abrasiveelement 101 is made thinner than its trailing edge 802 so that duringrotation of the drive shaft an abrasive surface 10001 of the abrasiveelement 101 may engage and abrade stenotic tissue only by a thickerportion of the abrasive element 101, said thicker portion 10002 of theabrasive element being spaced away from the leading edge 801 of theabrasive element 101. The abrasive element with thinner leading edge 801and thicker trailing edge 802 allows to gradually increase the degree ofengagement of the abrasive surface 10001 of the abrasive element 101with the stenotic tissue to be abraded. It should be noted thatvariation of the abrasive element shown in FIG. 56 may be used with anyembodiment of the rotational atherectomy device of the invention.

It should be noted that the rotational atherectomy devices with abrasiveelements which do not extend around the entire circumference of thedrive shaft may have advantages for crossing and abrading tight stenoticlesions. Preferably, abrasive elements which are attached to the driveshaft by straps should extend around less than a half of thecircumference of the drive shaft. The abrasive elements which extendaround less than a third of the circumference of the drive shaft mayallow the crossing and abrading of very tight stenotic lesions even whenthey are attached to the drive shaft by the straps which extend aroundthe entire circumference of the drive shaft. However, the abrasiveelements which extend around the entire circumference of the drive shaftand their fixations to the drive shaft known from WO 2006/126076 andother sources, may be used with any embodiments of this invention.

It should be noted that in the most preferred embodiments of theinvention, the fluid impermeable drive shaft is provided with two fluidinflatable support elements, one located at the distal end of the driveshaft and the other proximal to and spaced away from the abrasiveelement. FIGS. 1 through 8 illustrate one such embodiment in which thedrive shaft 2 is provided with both a distal fluid inflatable supportelement 10 and a proximal fluid inflatable support element 10 p. Theproximal fluid inflatable support element 10 p has an inner wall 111 pand an outer wall 222 p. In the most preferred embodiment of theinvention, the outer wall 222 p of the proximal fluid inflatable supportelement 10 p is formed by the outer layer 22 of the folded fluidimpermeable membrane 3. The inner wall 111 p of the proximal fluidinflatable support element 10 p is formed by the inner layer 11 of thefolded fluid impermeable membrane 3. The inner wall 111 p of theproximal fluid inflatable support element 10 p has an inflow aperture 15p therein. FIG. 2 illustrates that a portion of flushing fluid FFflowing in an antegrade direction along the drive shaft 2 is redirectedthrough the inflow aperture 15 p into the proximal inflatable supportelement 10 p to inflate said proximal inflatable support element. FIG. 2illustrates best that in order to form the proximal fluid inflatablesupport element 10 p, the inner 11 and outer 22 layers of the foldedfluid impermeable membrane 3 are connected or bonded to each other atleast just distal and proximal to the proximal fluid inflatable supportelement 10 p. In this location, just distal and proximal to the proximalfluid inflatable support element 10 p, the inner 11 and the outer 22layers of the membrane 3 are preferably connected or bonded to eachother around the entire circumference of the drive shaft 2.

It should be noted that the outer wall of the proximal fluid inflatablesupport element may be formed not only by a proximal portion of theouter layer 22 of the folded fluid impermeable membrane 3, but by aseparate fluid impermeable membrane 333 shown in FIG. 57. The separatefluid impermeable membrane 333 should be bonded circumferentially to thefluid impermeable membrane 3 at least just distal and proximal to theproximal fluid inflatable support element.

The following discussion is focused on the design and function of theproximal fluid inflatable support element 10 p which has its outer wall222 p formed by the outer layer 22 of the folded fluid impermeablemembrane 3, but it should be understood that the same discussion wouldbe applicable to a proximal fluid inflatable support element which hasits outer wall formed by the separate fluid impermeable membrane 333shown in FIG. 57. The following discussion is particularly applicablewith respect to the location and function of openings in the outer wallof the proximal fluid inflatable support element.

In the most preferred embodiments of the invention the outer wall 222 pof the proximal fluid inflatable support element 10 p has at least oneoutflow opening 20 p which enables flow of fluid out of the distendedfluid inflatable proximal support element 10 p. The proximal fluidinflatable support element 10 p becomes distended by flow of fluidthrough its inflow aperture 15 p which communicates the lumen of thefluid impermeable drive shaft 2 with the inflatable space 3000 p withinthe proximal fluid inflatable support element 10 p. The fluid inflatablespace 3000 p is at least partially defined by a fluid impermeablemembrane which forms an outer wall 222 p of the proximal fluidinflatable support element 10 p.

An area of the inflow aperture 15 p through which fluid enters theproximal inflatable support element 10 p is larger than the area of theoutflow opening(s) 20 p through which fluid exits the proximalinflatable support element 10 p so that the proximal fluid inflatablesupport element 10 p is kept inflated by the pressure of the fluidflowing through the proximal inflatable support element 10 p.

FIGS. 1, 2, 5 and 8 show the proximal fluid inflatable support element10 p which is asymmetric with respect to a longitudinal axis of thedrive shaft 2. FIGS. 1, 2, 5 and 8 show that, after being inflated byfluid, such asymmetric proximal support element 10 p has its centre ofmass CMp spaced away from the longitudinal axis W-W of the drive shaft2. FIGS. 1, 2, 4 and 7 show best an abrasive element 1 which is mountedto the drive shaft 2 distal to and spaced away from the asymmetricproximal fluid inflatable support element 10 p. As previously mentioned,the abrasive element 1 extends only around a portion of thecircumference of the drive shaft 2 and therefore has its centre of massspaced radially away from the longitudinal axis W-W of the drive shaft2. Preferably, the centre of mass CMp of the asymmetric fluid inflatedproximal support element 10 p is spaced radially away from thelongitudinal axis W-W of the drive shaft in one direction and the centreof mass of the abrasive element 1 is spaced radially away from thelongitudinal axis W-W of the drive shaft 2 in another diametricallyopposite direction, so that in a rotating drive shaft such asymmetricfluid inflated proximal support element 10 p forms (acts as) a proximalfluid inflatable counterweight with respect to the abrasive element 1

FIG. 2 illustrates that the outer wall 222 p of the fluid inflatedproximal support element 10 p is bowing longitudinally outwards at leastalong its longitudinally middle section which extends in a longitudinalcross-section between an outflow opening 20 p which is locatedlongitudinally most distally within the outer wall 222 p and anotheroutflow opening 20 p which is located longitudinally most proximallywithin the outer wall 222 p.

Each outflow opening 20 p in the outer wall 222 p of the proximal fluidinflatable support element has its own axis L-L. FIG. 2 illustrates thatthe asymmetric proximal fluid inflatable support element 10 p wheninflated has at least one outflow opening 20 p in its outer wall 222 plocated such that the axis L-L of the outflow opening 20 p forms anacute angle a of at least sixty (60) degrees with respect to thelongitudinal axis W-W of the drive shaft 2. In the most preferredembodiment of the invention, the asymmetric proximal fluid inflatablesupport element 10 p when inflated has at least one outflow opening 20 pin its outer wall 222 p located such that the axis L-L of the outflowopening 20 p forms about a ninety (90) degrees angle β with respect tothe longitudinal axis of the drive shaft 2.

FIGS. 15 through 26 illustrate that in the rotating asymmetric fluidinflated proximal support element 10 p at least one of the abovedescribed outflow openings 20 p is located such that its axis L-L formsabout a ninety (90) degrees angle with respect to the inner surface ofthe wall 300 of the treated vessel. Centrifugal force attempts to pressa rotating asymmetric fluid inflated proximal support element 10 pagainst the wall 300 of the treated vessel, but fluid exiting from theoutflow opening 20 p along its axis L-L at an angle of about ninety (90)degrees with respect to the wall 300 of the vessel forms a thin layer offluid between the rounded outer wall 222 p of the fluid inflatedproximal support element 10 p and an inner surface of the wall 300 ofthe vessel. The asymmetric fluid inflated proximal support element 10 phas its centre of mass spaced radially away from the longitudinal(rotational) axis of the drive shaft. Centrifugal force attempts topress the rotating fluid inflated proximal support element 10 p againstthe wall 300 of the vessel, but at least one outflow opening 20 p in thelongitudinally rounded outer wall 222 p of said rotating fluid inflatedproximal support element 10 p is located such that a flow of fluidthrough said opening 222 p forms a layer of fluid between the outer wall222 p of the rotating fluid inflated proximal support element 10 p andthe wall 300 of the treated vessel. Preferably, the fluid inflatedproximal support element 10 p with the centre of mass radially spacedaway from the longitudinal (rotational) axis of the drive shaft 2 shouldhave at least one outflow opening 20 p in the longitudinally roundedouter wall 222 p of the proximal inflatable support element 10 p locatedsuch that at any time during rotation of the drive shaft 2 said outflowopening 20 p is facing an inner surface of the treated vessel so that aflow of fluid through the outflow opening 20 p forms a layer of fluidbetween the longitudinally rounded outer wall 222 p of the rotatingfluid inflated proximal support element 10 p and the wall 300 of atreated vessel. Said layer of fluid forms a fluid bearing between theouter wall 222 p of the rotating fluid inflated proximal support element10 p and the wall 300 of the treated vessel.

FIGS. 50 and 51 illustrate the second most preferred embodiment of thedistal end portion of the rotational atherectomy device of theinvention. In this second most preferred embodiment, the distal fluidinflatable support element 10 s is symmetric with respect to alongitudinal axis W-W of the drive shaft. This symmetric distal fluidinflatable support element 10 s has a fluid inflatable space 3000 swhich extends uniformly around the drive shaft 2, so that after beinginflated by fluid the distal support element 10 s has its centre of masscoaxial with the longitudinal axis W-W of the drive shaft 2. An inflowopening (aperture) 15 s communicates the fluid inflatable space 3000 swithin the inflatable support element 10 s with the lumen of the fluidimpermeable drive shaft 2. The fluid inflatable space 3000 s is definedby a fluid impermeable membrane which forms at least a portion of thewall 222 s of the symmetric distal fluid inflatable support element 10s.

FIG. 51 illustrates in a longitudinal cross-section that the symmetricdistal fluid inflatable support element has a maximum diametercircumference when inflated and that the outer wall 222 s of the fluidinflated symmetric distal support element 10 s is bowing longitudinallyoutward at least along the maximum diameter circumference of theinflated symmetric distal support element.

The outer wall 222 s of the symmetric distal fluid inflatable supportelement 10 s has at least one outflow opening 20 s. Preferably, thesymmetric distal fluid inflatable support element 10 s has a pluralityof outflow openings 20 s in its outer wall 222 s. Each outflow opening20 s in the outer wall 222 s of the symmetric distal fluid inflatablesupport element 10 s has its own axis M-M. FIG. 51 illustrates that thesymmetric distal fluid inflatable support element 10 s when inflated hasat least one outflow opening 20 s in its outer wall 222 s located suchthat the axis M-M of the outflow opening 20 s forms an acute angle a ofat least sixty (60) degrees with respect to the longitudinal axis W-W ofthe drive shaft 2. In the second most preferred embodiment of theinvention, the symmetric distal fluid inflatable support element 10 swhen inflated has at least one outflow opening 20 s in its outer wall222 s located such that the axis M-M of the outflow opening 20 s formsabout a ninety (90) degrees angle β with respect to the longitudinalaxis W-W of the drive shaft. FIGS. 52 through 55 illustrate that in therotating symmetric fluid inflated distal support element 10 s at leastone of the above described outflow openings 20 s is located such thatits axis M-M forms about a ninety (90) degrees angle with respect to theinner surface of the wall 300 of the treated vessel. FIGS. 52 through 55also illustrate that in a curved vessel the drive shaft 2 attempts tomaintain its straight configuration and therefore attempts to press arotating symmetric distal fluid inflated support element 10 s againstthe outer curvature of the vessel but fluid exiting from the outflowopening 20 s along its axis M-M at an angle of about ninety (90) degreeswith respect to the wall 300 of the vessel forms a thin layer of fluidbetween the outer wall 222 s of the fluid inflated distal supportelement 10 s and the inner surface of the outer curvature of the wall300 of the treated vessel.

Preferably, the fluid inflated symmetric distal support element 10 sshould have a plurality of outflow openings 20 s located around thecircumference of the outer wall 222 s, the outflow openings 20 s locatedin a longitudinally bowing outward segment of the outer wall 222 s suchthat at any time during rotation of the drive shaft 2 at least one ofthese outflow openings 20 s is facing an inner surface of the treatedvessel so that a flow of fluid through the outflow opening 20 s forms alayer of fluid between the outer wall 222 s of the rotating fluidinflated symmetric distal support element 10 s and the wall 300 of thetreated vessel. Said layer of fluid forms a fluid bearing between theouter wall 222 s of the rotating fluid inflated distal support element10 s and the wall 300 of the treated vessel.

It should be noted that in the second most preferred embodiments of theinvention, the fluid impermeable drive shaft is provided with twosymmetric fluid inflatable support elements, one located at the distalend of the drive shaft and the other proximal to and spaced away fromthe abrasive element. FIGS. 50 and 51 illustrate the second mostpreferred embodiment of the invention in which the drive shaft 2 isprovided with both a symmetric distal fluid inflatable support element10 s and a symmetric proximal fluid inflatable support element 10 sp.The symmetric proximal fluid inflatable support element 10 sp has aninner wall 111 sp and an outer wall 222 sp. In the preferred embodimentof the invention, the outer wall 222 sp of the symmetric proximal fluidinflatable support element 10 sp is formed by the outer layer 22 of thefolded fluid impermeable membrane 3. The inner wall 111 sp of thesymmetric proximal fluid inflatable support element 10 sp is formed bythe inner layer 11 of the folded fluid impermeable membrane 3. The innerwall 111 sp of the symmetric proximal fluid inflatable support element10 sp has an inflow opening (aperture) 15 sp therein. This inflowopening (aperture) 15 sp communicates the lumen of the fluid impermeabledrive shaft 2 with an inflatable space 3000 sp within the symmetricproximal fluid inflatable support element 10 sp. The inflatable space3000 sp is at least partially defined by a fluid impermeable membranewhich forms the outer wall 222 sp of the symmetric proximal fluidinflatable support element 10 sp. FIG. 51 illustrates that a portion offlushing fluid FF flowing in an antegrade direction along the driveshaft 2 is redirected through the inflow opening (aperture) 15 sp intothe symmetric proximal fluid inflatable support element 10 sp to inflatesaid support element 10 sp. FIG. 51 illustrates best that in order toform the symmetric proximal fluid inflatable support element 10 sp, theinner 11 and outer 22 layers of the folded fluid impermeable membrane 3are connected or bonded to each other at least just distal and proximalto the symmetric proximal fluid inflatable support element 10 sp. Inthis location, just distal and proximal to the symmetric proximal fluidinflatable support element 10 sp, the inner 11 and the outer 22 layersof the membrane 3 are preferably connected or bonded to each otheraround the entire circumference of the drive shaft 2.

The outer wall 222 sp of the symmetric proximal fluid inflatable supportelement 10 sp has at least one outflow opening 20 sp. The symmetricproximal fluid inflatable support element 10 sp preferably has aplurality of outflow openings 20 sp in its outer wall 222 sp. Eachoutflow opening 20 sp in the outer wall 222 sp of the symmetric proximalfluid inflatable support element 10 sp has its own axis N-N. FIG. 52illustrates that the symmetric proximal fluid inflatable support element10 sp when inflated has at least one outflow opening 20 sp in its outerwall 222 sp located such that the axis N-N of the outflow opening 20 spforms an acute angle a of at least sixty (60) degrees with respect tothe longitudinal axis W-W of the drive shaft. In the second mostpreferred embodiment of the invention, the symmetric proximal fluidinflatable support element 10 sp when inflated has at least one outflowopening 20 sp in its outer wall 222 sp located such that the axis N-N ofthe outflow opening 20 sp forms about a ninety (90) degrees angle β withrespect to the longitudinal axis W-W of the drive shaft 2.

FIGS. 52 through 55 illustrate that in the rotating symmetric fluidinflated proximal support element 10 sp at least one of the abovedescribed outflow openings 20 sp is located such that its axis N-N formsabout a ninety (90) degrees angle with respect to the inner surface ofthe wall 300 of the treated vessel. FIGS. 52 through 55 also illustratethat in a curved vessel the drive shaft 2 attempts to maintain itsstraight configuration and therefore attempts to press the rotatingsymmetric proximal fluid inflated support element 10 sp against theouter curvature of the vessel but fluid exiting from the outflow opening20 sp along its axis N-N at an angle of about ninety (90) degrees withrespect to the wall 300 of the vessel forms a thin layer of fluidbetween the outer wall 222 sp of the fluid inflated proximal supportelement 10 sp and an inner surface of the wall 300 of the vessel.

Preferably, the fluid inflated symmetric proximal support element 10 spshould have a plurality of outflow openings 20 sp spaced about equallyaround the circumference of the outer wall 222 sp, the openings locatedsuch that at any time during rotation of the drive shaft 2 at least oneof these outflow openings 20 sp is facing an inner surface of thetreated vessel so that a flow of fluid through the outflow opening 20 spforms a layer of fluid between the outer wall 222 sp of the rotatingfluid inflated symmetric proximal support element 10 sp and the wall 300of the treated vessel. Said layer of fluid forms a fluid bearing betweenthe outer wall 222 sp of the rotating fluid inflated proximal supportelement 10 spand the wall 300 of the treated vessel.

FIGS. 52 through 55 illustrate the formation of fluid bearings betweenthe inner surface of the treated vessel and the outer walls of therotating fluid inflated support elements, each of the support elementshaving fluid inflatable space which extends circumferentially around theentire circumference of the drive shaft so that, in a curved vessel saidsupport elements are biasing the abrasive element towards the innercurvature of the curved vessel and allow preferential removal ofstenotic tissue from the inner curvature of the treated curved vessel.

It should be noted that the rotational atherectomy device comprisingsymmetrical fluid inflatable support elements may also be usedsuccessfully in a straight vessel where said elements, when supported byfluid bearings, allow safe rotation of the drive shaft within thetreated vessel even after the guidewire has been removed from therotational atherectomy device. The rotational atherectomy device withsymmetric fluid inflatable support elements preferably comprises eitheran eccentric abrasive element with a centre of mass spaced away from thelongitudinal axis of the drive shaft or, an abrasive element which iscapable of being magnetically biased in any direction with respect tothe circumference of the treated vessel.

FIGS. 58 to 60 shows how the drive shaft 2 may comprise a radiallyinwardly extending shoulder 79 located at or just proximal to the distalend 6 of the drive shaft 2. In this embodiment, the device comprises arounded element 80 configured to be advanced to a distal end 6 of thedrive shaft 2 where it is prevented from exiting the drive shaft 2 bythe radially inwardly extending shoulder 79, thereby occluding thedistal end 6 of the drive shaft 2 to at least partially prevent flow offluid through the distal end 6 of the drive shaft 2. The rounded element80 together with the inwardly extending shoulder 79 act as a ball-valvewhich assists in the redirection of the flow of fluid into the fluidinflatable support elements. In one embodiment, shown in FIGS. 61 and62, the radially inwardly extending shoulder is formed integrally withthe distal end 55 of the inner torque transmitting coil 44.

FIG. 63 illustrates the distal end portion of the drive shaft with anasymmetric fluid inflatable distal support element 10 and a solidasymmetric proximal support element 10 p, the fluid inflatable elementshown in its deflated state and, FIG. 64 illustrates the distal endportion of the drive shaft with an asymmetric fluid inflatable distalsupport element 10 and a solid asymmetric proximal support element 10 p,the fluid inflatable element shown in its inflated state.

It should be noted that the outer wall 222 sp of the symmetric proximalfluid inflatable support element 10 sp may be formed not only by aproximal portion of the outer layer 22 of the folded fluid impermeablemembrane 3, but by another fluid impermeable membrane.

It should be noted that the distal end portion of the device whichincludes fluid inflatable support elements may be manufacturedseparately from the rest of the device using manufacturing methods suchas injection moulding or insertion moulding.

It should be noted that a non-stretchable membrane should extend aroundthe drive shaft between the fluid inflatable elements when such elementsare formed from a fluid stretchable membrane.

It should be noted that any of the above discussions with respect to theconfiguration of the abrasive element and its attachment to the driveshaft with asymmetric fluid inflatable support element(s) are alsorelevant with respect to the drive shaft with symmetric fluid inflatablesupport element(s). The abrasive elements and their fixations to thedrive shaft known from WO 2006/126076 and other sources, may be usedwith any of the above described embodiments of this invention.

Many modifications and variations falling within the terms of thefollowing claims will be apparent to those skilled in the art and theforegoing description should be regarded as a description of thepreferred embodiments only.

1. A method of using a rotational atherectomy device for removing astenotic tissue from a blood vessel, the method comprising: inserting arotational atherectomy device into a blood vessel such that an abrasiveelement of the rotational atherectomy device is positioned proximate toa stenotic lesion, the rotational atherectomy device including: arotatable, flexible, hollow drive shaft including a torque transmittingcoil and a fluid delivery lumen for communicating fluid to the distalend portion of the drive shaft; the ail-abrasive element mounted to adistal end portion of the drive shaft and being fixedly positionedrelative to the circumference of the drive shaft; and proximal anddistal fluid inflatable counterweights fixedly positioned along thedistal end portion of the drive shaft on opposite sides of the abrasiveelement and being in fluid communication with the fluid delivery lumenof the drive shaft; rotating the drive shaft of the rotationalatherectomy device so that the abrasive element, the distal fluidinflatable counterweight, and the proximal fluid inflatablecounterweight rotate together with the distal end portion of the drive,wherein a center of mass of each of the proximal and distal fluidinflatable counterweights is offset from the longitudinal axis of thedrive shaft in a first direction while the center of mass of theabrasive element is offset from the longitudinal axis of the drive shaftin a second opposite direction; and delivering fluid through the fluiddelivery lumen of the drive shaft toward the distal end portion of thedrive shaft so as to cause a distal facing port at a distal-most end ofthe drive shaft is adjusted from an opened condition to a closedcondition.
 2. The method of claim 1, further comprising maintaining thedistal facing port of the drive shaft in the occluded condition duringsaid rotating of the drive shaft of the the rotational atherectomydevice.
 3. The method of claim 1, wherein said delivering the fluidcauses a movable element arranged in the drive shaft to adjust thedistal facing port of the drive shaft from the opened condition to theclosed condition.
 4. The method of claim 3, wherein the movable elementhas a size larger than the distal facing port of the drive shaft so thatthe movable element is retained inside the fluid delivery lumen, whereinthe movable element shifts to an occlusion position at the distal facingport of the drive shaft in response to fluid flow passing through thefluid delivery lumen of the drive shaft toward the distal end portion ofthe drive shaft.
 5. The method of claim 4, wherein the movable elementis configured to at least partially occlude the distal facing port ofthe drive shaft when shifted to the occlusion position so that the fluiddelivered through the fluid delivery lumen is directed to an internalspace of the distal fluid inflatable counterweight and an internal spaceof the proximal fluid inflatable counterweight.
 6. The method of claim5, wherein the movable element comprises a rounded element configured tobe advanced to the distal facing port of the drive shaft where it isprevented from exiting the distal facing port by a radially inwardlyextending shoulder.
 7. The method of claim 1, further comprising:advancing a guide wire though the blood vessel toward the stenoticlesion, receiving the guide wire in the fluid delivery lumen of thedrive shaft during advancement of the distal fluid inflatablecounterweight across the stenotic lesion in the blood vessel, andwithdrawing the guide wire away from the distal end portion of the driveshaft after the distal fluid inflatable counterweight advances acrossthe stenotic lesion in the blood vessel and before said rotating of thedrive shaft.
 8. The method of claim 1, further comprising, during saidrotating, outputting fluid flow through at least one outflow opening ofa flexible outer wall of each of the proximal and distal fluidinflatable counterweights.
 9. The method of claim 8, wherein the outflowopening of the distal fluid inflatable counterweight has an axis whichform an angle of about ninety (90) degrees with the longitudinal axis ofthe drive shaft when the distal fluid inflatable support element isinflated.
 10. The method of claim 8, further comprising forming a distalfluid bearing between the outer wall of the distal fluid inflatablecounterweight and a wall of the blood vessel during said outputtingfluid flow through said at least one outflow opening of the distal fluidinflatable counterweight.
 11. The method of claim 8, wherein the outflowopening of the proximal fluid inflatable counterweight has an axis whichform an angle of about ninety (90) degrees with the longitudinal axis ofthe drive shaft when the proximal fluid inflatable support element isinflated.
 12. The method of claim 8, further comprising forming aproximal fluid bearing between the outer wall of the proximal fluidinflatable counterweight and a wall of the blood vessel during saidoutputting fluid flow through said at least one outflow opening of theproximal fluid inflatable counterweight.